The Science Traceability Matrix (STM) typically adheres to a template provided in mission Announcements of Opportunity of NASA’s Science Mission Directorate (SOMA, 2018 ).
Science Goals (column 1) are broadly defined outcomes that increase knowledge and/or understanding of a scientific question, hypothesis, or phenomenon. In the Science Traceability Tool, the contents of this column are prescribed based on priority questions captured in the National Academies of Sciences, Engineering, and Medicine’s Origins, Worlds, and Life Planetary Science and Astrobiology Decadal Survey for the decade 2023-2032.
Science Objectives (column 2) are verifiable results, typically in the form of data and/or information, that must be credibly realizable (measurable) through the design and implementation of a mission, and that contribute significantly to the attainment of one or more Science Goals. In the Science Traceability Tool, the contents of this column are prescribed based on the user selection of potential biosignatures and target environment. Science Objectives can be defined more broadly or more specifically based on user preference. Examples of variations are available in the the Europa Lander and Enceladus Orbilander mission concept study reports.
Scientific Measurement Requirements (columns 3-4) are one or more qualitative or quantitative analyses performed to accomplish a science objective. One Objective can be achieved with several Measurements, so STM rows can be further split going from left to right. Measurement requirements comprise:
- Physical/Chemical Parameters (column 3): Specific and measurable quantities, qualities, states, conditions, or combinations thereof that characterize or provide data or information about a system, object, or configuration of matter and/or energy in a manner that achieves or addresses one or more Science Objectives.
- Observables (column 4): Particular qualities, quantities, or characteristics of a given Measurement Parameter that can be measured, quantified, or understood using a specified instrument, sensor, device, or system.
Because information in a STM must be traceable and flow logically, measurement requirements are typically defined in terms of one physical/chemical parameter and its corresponding observable. In the Science Traceability Tool, the contents of this column are very generically based on the user selection of potential biosignatures from the different categories (Chemistry, Structure, Activity). However, measurement requirements are typically more specific and quantitative.
Instrument requirements (column 5): The performance required from a specified instrument, sensor, device, or analysis system (typically, limits of detection, measurement range, resolution, immunity to interference, and other such metrics) in order to record/measure the Observable aspect(s) of a Measurement Parameter so as to provide results that partially or fully satisfy at least one Science Objective. Some information relevant to this column may be derived from contents in the Life Detection Knowledge Base (e.g., required limits of detection based on biotic/abiotic signal strength).
Projected performance (column 6): The anticipated/expected performance of a specified instrument, sensor, device, or analysis system that can be proven or demonstrated by the design, modeling, analysis, and most preferably, through the directly measured performance characterization of the instrument or system in a mission-like environment. Projected Performance should exceed the directly related Instrument Requirement by a margin consistent with uncertainties in the instrument, processing system, measurement, mission implementation, and environmental conditions. In the Science Traceability Tool, the contents of this column are left blank.
Mission requirements (top level) (column 7): An overarching set of requirements levied upon a mission and its design, informed by the complete set of performance-related aspects of the mission’s planned implementation, that impact, support, and enable the Instruments, Sampling Systems, and their operation and measurement processes to function and perform according to the stated Performance Projections and thereby achieve the Science Objectives, and, in so doing, address all Science Goals. This column typically comprises a single row pertinent to all objectives and measurements.